<template>
  <view>
    <view class="scroll-view-container">
      <!-- 左侧的滚动视图区域 -->
      <scroll-view class="left-scroll-view" scroll-y :style="{height: wh + 'px'}">
      <block v-for="(item, i) in cateList" :key="i">
            <view :class="['left-scroll-view-item', i === active ? 'active' : '']" @click="activeChanged(i)">{{item.cat_name}}</view>
       </block>
        
      </scroll-view>
<!-- 右侧的滚动视图区域 -->
      <scroll-view class="right-scroll-view" scroll-y :style="{height: wh + 'px'}" :scroll-top="scrollTop">
        <view class="cate-lv2" v-for="(item2, i2) in cateLevel2" :key="i2">
          <view class="cate-lv2-title">/ {{item2.cat_name}} /</view>
          <!-- 动态渲染三级分类的列表数据 -->
          <view class="cate-lv3-list">
            <!-- 三级分类 Item 项 -->
            <view class="cate-lv3-item" v-for="(item3, i3) in item2.children" :key="i3" @click="gotoGoodsList(item3)">
              <!-- 图片 -->
              <image :src="item3.cat_icon"></image>
              <!-- 文本 -->
              <text>{{item3.cat_name}}</text>
            </view>
          </view>
        </view>
      </scroll-view>
    </view>
  </view>
</template>

<script>
  export default {
    data() {
      return {
        wh:0,
        cateList:[],
        active:0,
        cateLevel2:[],
        scrollTop:0
      };
    },
    onLoad() {
         // 获取当前系统的信息
         const sysInfo = uni.getSystemInfoSync()
         // 为 wh 窗口可用高度动态赋值
         this.wh = sysInfo.windowHeight
         this.getCateList()
       },
       methods:{
         // 获取分类列表的数据
      async getCateList() {
      const {data:res} = await uni.$http.get('/api/public/v1/categories')
      if (res.meta.status !== 200) return uni.$showMsg()
        this.cateList = res.message
        this.cateLevel2 = res.message[0].children
         },
         activeChanged (i) {
           this.active = i
           this.cateLevel2 = this.cateList[i].children
           this.scrollTop = this.scrollTop === 0 ? 1 :0
         },
         // 跳转到商品列表页面
         gotoGoodsList(item) {
           uni.navigateTo({
             url:'/subpkg/goods_list/goods_list?cid='+item.cat_id
           })
         }
       }
  }
</script>

<style lang="scss">
 .scroll-view-container {
   display: flex;
 }
 .left-scroll-view {
   width: 120px;
 }
 .left-scroll-view-item {
   background-color: #F7F7F7;
   line-height: 60px;
   text-align: center;
   font-size: 12px;
     &.active {
       background-color: #FFFFFF;
       position: relative;
       &::before {
         content: ' ';
         display: block;
         width: 3px;
         height: 30px;
         background-color: #C00000;
         position: absolute;
         top: 50%;
         left: 0;
         transform: translateY(-50%);
       }
     }
    
 } 
 .cate-lv2-title {
       font-size: 12px;
       font-weight: bold;
       text-align: center;
       padding: 15px 0;
}
.cate-lv3-list {
  display: flex;
  flex-wrap: wrap;

  .cate-lv3-item {
    width: 33.33%;
    margin-bottom: 10px;
    display: flex;
    flex-direction: column;
    align-items: center;

    image {
      width: 60px;
      height: 60px;
    }

    text {
      font-size: 12px;
    }
  }
}
 
</style>
